This thesis is missing page 129, no other copy of the thesis has this page. Based on the figure list and last page, it is our belief that the thesis was incorrectly number and should end on Figure 17. -Digitization Centre / Many medical researchers in the post-WWII era explored LSD for its potential therapeutic value. Among these psychiatrists Humphry Osmond (in Weyburn) and Abram Hoffer (in Saskatoon) directed some of the most comprehensive trials in the Western world. These Saskatchewan-based medical researchers were first drawn to LSD because of its ability to produce a "model psychosis." Their experiments with the drug that Osmond was to famously describe as a "psychedelic"-led them to hypothesise, and promote, the biochemical constitution of Schizophrenia. Simulating psychotic symptoms through auto-experimentation, professionals also believed that the drug would help reform mental health accommodations by cultivating a sophisticated appreciation for the relationship between environment and health. This thesis examines the era of pre-criminal LSD experimentation. Drawing on hospital records, interviews with former research subjects, and the private papers of Hoffer and Osmond this dissertation will demonstrate that these LSD trials, far from fringe medical research, represented a fruitful and indeed encouraging branch of psychiatric research. Clinical LSD experiments in the 1950s played an influential role in defining theoretical and practical aims of the post-war psychiatric profession. Ultimately the experiments failed for two reasons, one scientific and the other cultural. The scientific parameters of clinical trials in medicine shifted in the 1950s and early 1960s so as to necessitate controlled trials (which the Saskatchewan researchers had failed to construct). Second, as LSD became increasingly associated with student riots, anti-war demonstrations and the counter culture, governments intervened to criminalise the drug, in effect terminating formal medical research with LSD. An historical examination of these LSD experiments provides insight into the changing complexion of psychiatry in the post-World War Two period, and the ways in which scientific medicine was shaped by social, cultural and political currents. / Dissertation / Doctor of Philosophy (PhD)